WO 2010/058013 A2 discloses a method for forwarding operating data to a monitoring unit, said operating data relating to the present operation of a plurality of inverter units. The inverter units feed electrical power into a supply network. In the known method, the inverter units are connected to the central monitoring unit via a plurality of interposed data handling units in a network having a logical tree architecture. The operating data are forwarded from each inverter unit to the interposed unit to which the inverter unit is connected. In each interposed unit that forwards the operating data, operating data of the same type are combined in order to reduce the data volume. Only the combined operating data are forwarded. The forwarding of the operating data to the central unit can be initiated by a generic request that is output by the monitoring unit and indicates that each unit in the communication network that is able to supply the operating data asked for should do so. The operating data can also be regularly forwarded from one unit to the next in the communication network toward the monitoring unit on account of a subscription of the operating data. A further monitoring unit can also be connected to the communication network. Operating data already present are managed in a data handling unit that is usable as an interposed unit in this known method. The data handling unit comprises a connection port for receiving requests for values from a superordinate unit and for forwarding the operating data asked for to the superordinate unit, and a further connection port for sending request data for values to a plurality of subordinate units and for receiving the requested operating data from the subordinate units. In the known method, the requests for operating data and the forwarding of the requested operating data are carried out across all levels of the communication network according to a specific protocol that makes it possible to combine operating data of the same type that are forwarded by the plurality of inverter units, without the data model of the data being altered.
The method known from WO 2010/058013 A2 is suitable only for communication between inverter units, data handling units and monitoring units set up specifically for this method.
DE 10 2012 109 060 A1 discloses a method for communication with decentralized devices that handle electrical energy via the Internet. In this known method, from the devices and from potential communication partners of the devices, data are communicated to a server via the Internet, said data in each case comprising a communication address and furthermore attributes indicating generic properties of the devices and of the communication partners. As a reaction to an initializing time-variable datum, the server establishes a communication connection between at least one specific device and at least one specific communication partner via the Internet. For this purpose, rules are programmed in the server, which rules, on the basis of the attributes of the devices and of the communication partners and the initializing time-variable datum, stipulate between which device and which communication partner the communication connection is established. The communication connection can be a point-to-point connection, a point-to-multipoint connection or a multipoint-to-multipoint connection.
The method known from DE 10 2012 109 060 A1 also presupposes, for successful communication between the respective devices and the communication partners thereof, that they are suitable for direct data exchange among one another.
DE 10 2007 022 879 A1 discloses an inverter for grid feeding into an AC grid, which inverter, on the input side, is connectable to a generator that generates electrical energy, and comprises a data connection to a data network to which are connected a multiplicity of further inverters with further electricity generators for feeding electricity into the AC grid. The data network together with the connected inverters forms a communication unit, wherein the individual inverters are controlled by a control unit via the data network such that a power plant unit that is uniform with regard to feeding-in parameters is present. Said power plant unit can be connected as an external unit having a combined supervisory and control structure in an interconnected electricity grid. It is also referred to as a virtual power plant. However, such a virtual power plant presupposes the suitability of all associated inverters for being connected to the data network such that they are controllable by the control unit via the data network.
WO 2011/116770 A2 discloses a method and a system for providing data from a subordinate device to a superordinate computer connected to the superordinate device. In that case, a data stream between the subordinate device and the superordinate computer is translated from a low data format to a higher data format in the superordinate computer. The translation function comprises static data relating to the subordinate device. The higher data format is used to display data from the subordinate device at the superordinate computer. In this regard, the data from the subordinate device can be accessed via the communication interfaces of the superordinate computer.
Naumann, B.-M. Buchholz, P. Komarnicki, Ch. Brunner: “Seamless data communication over all levels of the power system”; CIRED, Proceeding of the 21st International Conference and Exhibition on Electricity Distribution, Frankfurt am Main, Jun. 6-9, 2011 (http://www.cired.net/publications/cired2011/part1/papers/CIRED2011 0988 final.pdf) discloses a method for communication within an energy supply system with a plurality of spatially distributed energy generating systems in order to form a virtual power plant. In order to combat the problem of different communication protocols and information systems that do not enable seamless exchange of information between the different levels of the energy supply system, a homogeneous protocol between and within all levels of the energy supply system is described. Units, such as measuring instruments and automation devices, which do not use said homogeneous profile themselves are provided with gateways in order to be able to communicate with them as well via the homogeneous protocol. Even with a common information model that internally follows a different standard, all units communicate via the homogeneous protocol, the values of which are mapped onto the corresponding attributes of the standard of the common information model.
The increasing prevalence of decentralized energy generating systems connected at different points to a supply network for electrical energy makes it increasingly difficult to monitor and influence parameters of such a supply network and, in particular, to effect targeted concerted control of all or at least all important energy generating systems that are connected to the supply network. These difficulties increase greatly with the number of data models in which the energy generating systems output their operating data. This holds true particularly if a plurality of system control units are present which in parallel want to request system data from the energy generating systems and/or to influence the operation of the energy generating systems. One example of parallel interventions by two system control units is a network control center that is intended to balance the supply of electrical power and the consumption of electrical power over the entire supply network, and a local monitoring device that is intended to comply with specific network parameters at specific points of the supply network. In this case, a local equilibrium of supply and demand of electrical power may be of importance for complying with said network parameters, which local equilibrium may be disturbed even if the supply of and the demand for electrical power in the supply network overall are balanced.
Considerable effort is currently being expended in order to upgrade energy generating systems for communication with different system control units. For this purpose, with high outlay, the energy generating systems are provided with different interfaces adapted to the potential interfaces of the system control units. Even if many different interfaces were set up at an energy generating system, over the planned long lifetime of an energy generating system it is nevertheless likely, however, that it will not have a matching interface for a new system control unit using a newer data model.